AZ31镁合金热轧变形的动态再结晶机制

DRX Mechanism of AZ31 Magnesium Alloy during Hot Rolling

摘要:

在轧制温度603~703 K、轧制压下量20%~40%、应变速率4~16 s-1下对AZ31镁合金进行轧制变形，研究轧制压下量、应变速率和变形温度对AZ31镁合金变形组织的影响，分析了镁合金的动态再结晶机制。结果表明：应变速率和变形温度不仅影响动态再结晶进行的程度，而且能够改变再结晶的方式或形核机制。当轧制应变速率= 13.9 s-1，变形温度T=603 K时，再结晶方式为孪生动态再结晶；变形温度升高到703 K时，沿晶界有链状新晶粒出现。当变形温度T= 673 K，应变速率= 11.35 s-1时，再结晶方式以孪生动态再结晶为主；应变速率降低到= 4 s-1时，再结晶方式以旋转动态再结晶为主。

Abstract:

AZ31 Mg alloy was rolled at the temperature ranging from 603 K to 703 K with reduction from 20% to 40% and strain rate from 4 s-1 to 16 s-1. The effect of reduction per pass, strain rate and rolling temperature on the microstructure of the deformed Mg alloy was studied. The dynamic recrystallization (DRX) mechanism of AZ31 Mg alloy during hot rolling was investigated. The results demonstrate that the strain rate and the temperature not only affect the extent of DRX, but also change the mode of DRX or nucleation mechanism. When the strain rate is = 13.9 s-1, the DRX mode is twinning-induced DRX at T=603 K; but there appear some new chain-like grains along the original grain boundaries at T=703 K. When the temperature is T= 673 K, DRX is mainly twinning-induced DRX at the strain rate = 11.35 s-1, while with the strain rate decreasing to = 4 s-1, the DRX mode turns into rotation DRX.